The present invention relates to a video detector apparatus and more particularly to a video synchronous detector apparatus having a picture-carrier intermediate frequency extraction circuit capable of reducing a socalled sound-cross-color disturbance.
It is known in the art to carry out a video synchronous detection by means of multiplying a picturecarrier intermediate frequency extracted from a video intermediate frequency signal (hereinafter referred to as VIF signal) through a picture-carrier intermediate frequency extraction circuit by the original VIF signal which is not routed to the picture-carrier intermediate frequency extraction circuit. In a prior art synchronous detection of the type described above, however, a side band component which is an amplitude-modulated component by the video signal remains not fully attenuated in the signal to be applied to the multiplier circuit. Particularly, when a brightness changes steeply from a black level to a white level, a colored flicker disturbance appears in their boundary portion.